I've done some checking on your video. Definitely doesn't look easy to reduce the file size. Finally found a nice bitrate histogram tool (
Bitrate Viewer), so it becomes much easier to see where the issues lie.
Histogram for your video:

As you can see, there are 4 high-bitrate areas. A few seconds each around 20 and 36 seconds (both around 25 Mbps each, avg), and then two longer periods (around 12 Mbps each)? 20 and 36 are high-noise scenes, and the two longer periods are the segments with the banner scrolling and staticy video footage.
This type of high-bitrate profile
only shows up when there's lots of noise in the scene. Running through a bunch of other contest vids, it took a while to find one that wasn't fairly flat over the entire video. The first one I found to have spikes was "[HaydenST] Time for Life" from Quickening round C-2; it's the TGWLTT video, with lots of 'old film' noisy footage filters, and it's exactly those filtered portions that jack up the bit rate. It was also a very large file, at 116 MB.
While there are certain tweaks you can make in Zarx's package to improve the video a bit, there's not a lot you can do if you want to use those types of noisy effects; they are inherently bitrate-hungry. If using CRF, you can mess with VBV settings to maybe put a cap on bitrate (this is probably the better solution, but it's complicated, and I'm not familiar enough with it to offer any suggestions on how to go about it)? Otherwise, if you really want to drop the file size, your best bet is probably a 2-pass encode. Average for your 102 MB encode is 6000 kbps, so you can scale it down proportionately to how large you want the final file to be.